42 THE WORLD OF LIFE 



area of about 4 square miles of uncultivated land some miles 

 away. That this latter is quite possible is shown by my 

 friend Mr. Henry Deane, who has for many years studied 

 the flora of 20 square miles of country around Hunter's Hill, 

 on the Paramatta Kiver, to the north-west of Sydney, and he 

 here obtained 59 species of Orchids out of a total of 618 

 flowering plants. The sequence of the first eight orders in 

 number of species is as follows : — 



1. Orchidese 51) 



2. Myrtaceae 5.5 



3. Leguminosse 53 



4. Pioteacese 35 



5. Compositae 32 



6. Graminese 31 



7. Cyperacese 30 



8. Epacridese 25 



In XcAv South Wales, as a Avhole, Leguminosse are first 

 and Orchids fifth in order. There is probably no other 

 purely temperate flora in which Orchids so distinctly take 

 the first place as in the vicinity of Sydney. 



The contrast in the numbers of species, in approximately 

 comparable areas, between these two groups of waiTQ-temperate 

 floras is fairly well marked throughout, there being, with few 

 exceptions, a decided preponderance in the southern hemis- 

 phere. South Africa is undoubtedly richer than China, though 

 its area is less ; and perhaps than the oriental region of Bois- 

 sier; Avhile Chili compares favourably with Japan or the West- 

 ern Himalayas. Still, the differences are not very pronounced, 

 and are such as appear due to their past history rather than to 

 any existing conditions. Those in the northern hemisphere 

 (except perhaps in the case of the Mediterranean coasts) have 

 probably been for a considerable period stationary or expand- 

 ing; while those in the south have almost certainly been far 

 more extensive, and in later geological time have been contrac- 

 ting, and thus crowding many species together, as already ex- 

 plained. 



